Gateway apparatus and method for synchronization between heterogeneous network domains within vehicle

Abstract

A gateway apparatus includes a first network controller, a second network controller, and a time synchronization control unit. The first network controller has a first timer time-synchronized with nodes within a first network domain. The second network controller has a second timer time-synchronized with nodes within a second network domain. The time synchronization control unit includes a processor configured to store the observed times of the switching points of synchronized time slots within the first network domain, based on system time within the second network domain, and adjusts the rate of the second timer based on a comparison of a time difference between the successive observed times and a nominal length of the time slots.

What is claimed is: 
     
       1. A gateway apparatus to synchronize between heterogeneous network domains, the gateway apparatus comprising:
 a first network controller comprising a first timer time-synchronized with nodes within a first network domain; 
 a second network controller comprising a second timer time-synchronized with nodes within a second network domain; and 
 a time synchronization control unit configured to store observed times of switching points of synchronized time slots within the first network domain based on system time within the second network domain, and to adjust a rate of the second timer based on a result of a comparison of a time difference between the successive observed times and a nominal length of the time slots. 
 
     
     
       2. The gateway apparatus of  claim 1 , wherein the first network domain is constructed based on FlexRay communication. 
     
     
       3. The gateway apparatus of  claim 1 , wherein the second network domain is constructed based on vehicle Ethernet communication. 
     
     
       4. The gateway apparatus of  claim 1 , wherein a tick of the first timer is longer than a tick of the second timer, and a length of the time slots is shorter than a synchronization period of the second network domain. 
     
     
       5. The gateway apparatus of  claim 1 , wherein the time synchronization control unit is further configured to control the second network controller to adjust timers of the nodes within the second network domain based on the second timer according to a time synchronization protocol that operates in a synchronization period within the second network domain, in response to the second network controller being designated as a master of the time synchronization protocol. 
     
     
       6. The gateway apparatus of  claim 1 , wherein the time synchronization control unit is further configured to adjust an offset and a rate of the second timer based on an offset and a rate determined according to a time synchronization protocol that operates in a synchronization period within the second network domain, in response to the second network controller being designated as a slave of the time synchronization protocol. 
     
     
       7. The gateway apparatus of  claim 1 , wherein the first network domain is configured to use time division deterministic communication. 
     
     
       8. The gateway apparatus of  claim 1 , wherein the second network domain is configured use contentious communication. 
     
     
       9. A method to synchronize between heterogeneous network domains, the method comprising:
 time synchronizing a first timer with respect to nodes within a first network domain using a first network controller; 
 time synchronizing a second timer with respect to nodes within a second network domain using a second network controller; 
 storing observed times of switching points of synchronized time slots within the first network domain based on system time within the second network domain; and 
 adjusting a rate of the second timer based on a result of a comparison of a time difference between the successive observed times and a nominal length of the time slots. 
 
     
     
       10. The method of  claim 9 , wherein the first network domain is constructed based on FlexRay communication. 
     
     
       11. The method of  claim 9 , wherein the second network domain is constructed based on vehicle Ethernet communication. 
     
     
       12. The method of  claim 9 , wherein a tick of the first timer is longer than a tick of the second timer, and a length of the time slots of the first network domain is shorter than a synchronization period of the second network domain. 
     
     
       13. The method of  claim 9 , further comprising controlling the second network controller to adjust timers of the nodes within the second network domain based on the second timer in accordance with a time synchronization protocol that operates in a synchronization period within the second network domain, in response to the second network controller being designated as a master of the time synchronization protocol. 
     
     
       14. The method of  claim 9 , further comprising, adjusting an offset and a rate of the second timer based on an offset and a rate determined in accordance with a time synchronization protocol that operates in a synchronization period within the second network domain, in response to the second network controller being designated as a slave of the time synchronization protocol. 
     
     
       15. A non-transitory computer-readable medium storing instructions that, when executed by a processor, cause the processor to perform the method of  claim 9 .